This invention pertains to a clockspring interconnector for enclosing an electrical conductor cable, the clockspring interconnector electrically connecting a rotatable electric device with a stationary electric device.
An increasing number of automobiles have air bag crash systems. An air bag is typically located on the steering wheel facing the driver. The air bag must be in continuous electrical connection with sensors in the car body. The sensors provide an electrical signal to the air bag crash assembly which instantly inflates the air bag in the event of a crash.
Accordingly, there is a need for an electrical connection between the rotatable portion of the air bag assembly which is mounted to the steering wheel, and the remaining portion of the assembly, which is in a stationary position in the car body. Electrical connections between rotatable and stationary parts are well known. Typically, an electrical brush rests upon a conductive ring, with one of the parts being rotatable to provide such rotatable electrical connection. However, there is a risk, particularly during the impact of an accident, of a transient failure of electrical connection with a brush and ring system, which would result in failure of the entire air bag system crash assembly.
Accordingly, a clockspring interconnector has been previously developed, comprising an outer housing, a rotor member and multiple intermediate housing members for enclosing and connecting the members; the housing and rotor member rotatably associated with one another at a plurality of bearing surfaces. A "clockspring" is located inside the interconnector. The clockspring is a flat conductor cable and has two ends conductively attached to conductor wires which pass out of the interconnector to unite the air bag to the sensing device. The interconnector is mounted on the steering column, and the steering wheel may be rotated in either direction while a continuous, positive electrical connection is provided between air bag sensors via the clockspring interconnector.
While prior art clockspring interconnectors are effective to provide the necessary continuous electrical connection between an air bag or other device on a rotating column and a stationary portion of a circuit, the prior art systems do not provide for proper reduction of noise which occurs due to vibration of the flat cable within the clockspring housing. It is known in the prior art to include insulation materials within a clockspring housing in order to deaden the sound created by the scraping of the flat cable during rotation of the clockspring. However, there is additional noise created while the clockspring is stationary due to vibrations caused by the movement of the automobile. The vertical vibration of a steering column causes the flat cable of a clockspring to vibrate and rattle against the adjacent coils of the flat cable. Accordingly, there is desired a clockspring which includes a vibration dampener to avoid the above disadvantages.
It has been disclosed in U.S. Pat. No. 4,925,122 to have presser members which are secured to the wails of the housing of a clockspring and provide pressure against the flat cable. This invention is disadvantageous in that the presser members are complicated to install within a clockspring and are expensive to manufacture. The presser members also provide only minimal points of contact to compress the flat cable. Thus, there is needed a vibration dampener which is quickly and easily installed and is inexpensive to manufacture. Also, a vibration dampener which provides multiple points of contact to a flat cable for compression would be advantageous.
It is an object of the present invention to provide a clockspring assembly including a vibration dampener to greatly reduce the vibration of the flat cable of a clockspring.
It is another object of the present invention to provide a clockspring assembly, including a sound dampener which is easily incorporated into a clockspring assembly and is inexpensive to manufacture.